Compressor Casing Assembly Providing Access To Compressor Blade Sealing Assembly

ABSTRACT

A compressor casing assembly includes a forward compressor casing, a removable cover and a seal assembly. A midcompressor casing is provided with a cavity adapted to receive the seal assembly, and a cover groove adapted to receive the removable cover. The removable cover secures the seal assembly.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of copending application Ser.No. 13/610,269 titled “REPLACEABLE SEALS FOR TURBINE ENGINE COMPONENTSAND METHODS FOR INSTALLING THE SAME” filed on Sep. 11, 2012, which ishereby incorporated by reference.

TECHNICAL FIELD

The subject matter disclosed herein relates generally to turbine enginecomponents and, more specifically, to compressor casing assemblies.

BACKGROUND

Turbine engines operate according to well-known principles wherein anincoming stream of atmospheric air flows through the engine along anaxially-extending flow path. In at least some turbine engines, at leasta portion of the incoming air is compressed in a compressor section ofthe engine and is then mixed with fuel and ignited in a combustorsection to produce a high-energy, high-temperature exhaust gas stream.The hot gas stream exits the combustor and is channeled through aturbine section that extracts energy from the exhaust stream to powerthe compressor and to provide useful work, such as powering an aircraftin flight or producing electricity.

In the compressor and turbine sections of known gas turbine engines,blades rotate about the center axis of the engine. Engine efficiencydepends at least partially on minimizing leakage in an effort tomaximize interaction between the gas stream and blades. Within knownturbines, one source of inefficiency is leakage of gas past the tips ofthe blades and between the blade tips and the surrounding engine casing.Although a close tolerance fit may be obtained by fabricating the matingparts to a close tolerance range, such a fabrication process is costlyand time-consuming, and may result in rubbing an inner surface of thecasing.

As such, to increase engine efficiency, at least some turbines use asealing element along the inner surface of the casing, to reduce leakagebetween the blade tips and the casing. Various sealing techniques havebeen used. Generally, known sealing elements lose effectiveness overtime and may require replacement.

However, in order to replace known sealing elements, the engine casingand the rotor must be removed from the engine to provide workers accessto the sealing elements. Such a process significantly increases themaintenance costs and may cause a prolonged duration in engine outages.

BRIEF DESCRIPTION OF THE INVENTION

The disclosure provides a solution to the problem of having to removethe midcompressor casing of a turbine engine in order to access the zerostage seal assembly of the compressor.

In accordance with one exemplary non-limiting embodiment, the inventionrelates to a compressor casing assembly. The compressor casing assemblyincludes a forward compressor casing; a removable cover and a sealassembly. The compressor casing assembly also includes a midcompressorcasing having a cavity adapted to receive the seal assembly, and a covergroove adapted to receive a removable cover that secures the sealassembly.

In another embodiment, a turbine engine is provided having amidcompressor casing having a face surface and an inner surface, thecompressor casing having a cavity formed on the inner surface and agroove formed on the face surface. The turbine engine also includes aplurality of arcuate seal segments configured to be inserted into thecavity, and a removable cover disposed in contact with the arcuate sealsegments and being removably secured to the midcompressor casing.

In another embodiment, an assembly is provided having a midcompressorcasing having a face surface and an inner surface, the inner surfacehaving a cavity and the face surface having a cover groove. The assemblyincludes a plurality of arcuate seal segments configured to be insertedinto the cavity. The assembly also includes a removable cover adapted tobe inserted into the cover groove, the removable cover is disposed incontact with at least some of the plurality of arcuate seal segments andsecured to the compressor casing.

Other features and advantages of the present invention will be apparentfrom the following more detailed description of the preferredembodiment, taken in conjunction with the accompanying drawings whichillustrate, by way of example, the principles of certain aspects of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a turbine engine taken along alongitudinal axis of the turbine engine.

FIG. 2 is a detailed cross sectional view of an embodiment of the casingassembly.

FIG. 3 is a cross-sectional view of an embodiment of a seal assembly.

FIG. 4 is a cross-sectional view of an embodiment of a midcompressorcasing.

FIG. 5 is a cross-sectional view of an embodiment of a removable cover.

FIG. 6 is an axial view of the first compressor stage and illustrates anexemplary seal assembly.

DETAILED DESCRIPTION OF THE INVENTION

The embodiments disclosed herein provide for easy access to a zero stageseal assembly without removal of a midcompressor casing. This isaccomplished with a removable cover that is secured to the midcompressorcasing that serves to hold the zero stage seal assembly in place.Removal of the removable cover provides access to the zero stage sealassembly.

FIG. 1 is a cross-sectional view of a turbine engine 11 taken through alongitudinal axis 12 extending through the turbine engine 11. In theexemplary embodiment, turbine engine 11 also includes a compressor 13having a plurality of rotor blades 15 that are circumferentially spacedand that extend radially outward towards a midcompressor casing 17 froma rotor wheel 19 which collectively form the rotor shaft. Stator vanes20 are positioned adjacent to each set of rotor blades 15, and incombination form one of a plurality of stages 21. Stator vanes 20 aresecurely coupled to midcompressor casing 17 and extend radially inwardto interface with rotor wheel 19. Each of the plurality of stages 21directs a flow of compressed air through compressor 13. Rotor blades 15are circumscribed by midcompressor casing 17, such that an annular gap(not shown in FIG. 1) is defined between midcompressor casing 17 and arotor blade tip 23 of each of the rotor blades 15.

Each gap is sized to facilitate minimizing a quantity of compressed airthat bypasses the rotor blades 15. Specifically, in the exemplaryembodiment, a seal assembly 25 is used between midcompressor casing 17and rotor 26 to substantially seal the gap defined therebetween.Specifically, seal assembly 25 facilitates reducing bypass flow ofcompressed air between midcompressor casing 17 and rotor blade tip 23.In the exemplary embodiment, compressor 13 includes eighteen separatestages 21. Alternatively, seal assembly 25 as described herein may beemployed in any suitable type of compressor with any number of stages.An inlet guide vane (IGV 27) is positioned upstream form the rotorblades 15. IGV 27 directs the airflow onto the rotor blades 15.

During operation, air flows into turbine engine 11 through intake 16 andtowards compressor 13. Stator vanes 20 direct the compressed air towardsrotor blades 15. The compressed air applies motive forces to rotorblades 15 to compress the air flowing through each of the plurality ofstages 21.

Illustrated in FIG. 2 is an enlarged view of the detail area 29 shown inFIG. 1 illustrating a casing assembly 31. Casing assembly 31 is disposedadjacent to IGV 27, zero stage rotor 35 and zero stage stator 37. Zerostage seal assembly 39 is disposed adjacent to zero stage rotor 35.Casing assembly 31 includes a midcompressor casing 17 and a forwardcompressor casing 22. Midcompressor casing 17 and forward compressorcasing 22 are fastened by means of casing fastener(s) 41. Casingassembly 31 also includes a removable cover 43 disposed between theforward compressor casing 22 and the midcompressor casing 17. Removablecover 43 is an arcuate member (has arcuate shape). Casing assembly 31also includes a zero stage seal assembly 39 that is secured tomidcompressor casing 17 by removable cover 43. Zero stage seal assembly39 includes a removable seal support 45 and a seal 47.

Removable cover 43 may be fastened to midcompressor casing 17 by meansof cover fasteners 49. The removable seal support and seal are joined bymeans of seal fasteners 51.

FIG. 3 is a detailed cross section of zero stage seal assembly 39. Zerostage seal assembly 39 includes a t-shaped member 63 having a base 65, atop surface 66, a first projection 67, a side surface 68 and a secondprojection 69. Seal 47 may include an abradable seal surface, ahoneycomb seal surface, a brush seal surface, and/or any seal surfacethat enables the zero stage seal assembly 39 to function as describedherein. Seal surface 70 may be thermally sprayed, brushed, and/or baked,and may be fabricated from a metallic material, a ceramic material, orany other material that enables seal surface 70 to function as describedherein. Seal surface 70 may include a plurality of bristles formed froma metallic or non-metallic material, such as ceramics, carbon fiber,and/or silica.

FIG. 4 is a cross section of a portion of the midcompressor casing 17.The midcompressor casing 17 has a face surface 71, a horizontal innersurface 73 and a vertical inner surface 75. Midcompressor casing 17 hasa notch 77 configured to engage the first projection 67 of the zerostage seal assembly 39. The midcompressor casing 17 is additionallyprovided with a cover groove 79 configured to engage the removable cover43.

FIG. 5 is a cross-section of the removable cover 43. Removable cover 43is provided with a cover notch 81 configured to engage second projection69 of the zero stage seal assembly 39.

When installed, forward compressor casing 22 is fastened tomidcompressor casing 17 and the zero stage seal assembly 39 is disposedin the cavity 82 formed by horizontal inner surface 73, vertical innersurface 75 and notch 77. The zero stage seal assembly 39 is positionedso that first projection 67 of the zero stage seal assembly 39 isdisposed in the notch 77 in the midcompressor casing 17. Thisconfiguration prevents movement of the zero stage seal assembly 39 in aradial direction. The zero stage seal assembly 39 is secured in placewith the removable cover 43. Cover notch 81 is configured to engagesecond projection 69 of the zero stage seal assembly 39. Forwardcompressor casing 22 and midcompressor casing 17 maintain the removablecover 43 in place during operation.

FIG. 6 is an axial view along longitudinal axis 12 of the first of theplurality of stages 21 looking aft with the forward compressor casing 22removed. The midcompressor casing 17 may include a casing upper half 87and a casing lower half 89. The removable seal support 45 may include aplurality of arcuate seal segments 90 such as first upper seal segment91, first lower seal segment 93, second lower seal segment 95, andsecond upper seal segment 97 that are removably coupled to an innersurface of midcompressor casing 17. Each of the plurality of arcuateseal segments 90 include a sealing surface extending a fullcircumferential length along each of the plurality of arcuate sealsegments 90. The sealing surface extends a distance above and below aradially inner surface of the midcompressor casing 17 when each of theplurality of arcuate seal segments 90 is coupled the midcompressorcasing 17. In the exemplary embodiment, the seal assembly 25 includesfour seal segment, but may include any number of seal segments thatenables seal assembly 25 to function as described herein. The removablecover 43 is fastened to the midcompressor casing 17 with cover fasteners49. The removable cover 43 has a longer peripheral length than any oneof the arcuate seal segments 90 (e.g. first upper seal segment 91) sothat the individual seal segments can be inserted into the midcompressorcasing 17 The fasteners may be countersunk into the removable cover 43and positively captured by the rear face of the forward compressorcasing 22. Upon removal of the removable cover 43 access is provided tothe end of a removable seal support 45 within either casing upper half87 or within casing lower half 89. The removable seal support 45 isremovably and slidably coupled to midcompressor casing 17. Access to theremovable sealing element is provided without having to remove themidcompressor casing 17. Forward face of midcompressor casing 17 may beturned to permit the installation & removal of removable seal support 45once access is gained when the forward compressor casing 22 is removed.The removable cover 43 is screwed into the midcompressor casing 17 andis positively captured by the rear face of the forward compressor casing22 during normal operation, eliminating any risk of loose parts causingforeign object damage to the compressor 13.

The casing assembly 31 enables the replacement of a zero stage sealassembly 39 without removal of the midcompressor casing 17. The operatorcan move the zero stage seal assembly 39 by first removing the forwardcompressor casing 22. This provides access to the removable cover 43which can then be removed to provide access to the various components ofthe zero stage seal assembly 39 which can then be easily removed.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention.Where the definition of terms departs from the commonly used meaning ofthe term, applicant intends to utilize the definitions provided herein,unless specifically indicated. The singular forms “a”, “an” and “the”are intended to include the plural forms as well, unless the contextclearly indicates otherwise. It will be understood that, although theterms first, second, etc. may be used to describe various elements,these elements should not be limited by these terms. These terms areonly used to distinguish one element from another. The term “and/or”includes any, and all, combinations of one or more of the associatedlisted items. The phrases “coupled to” and “coupled with” contemplatesdirect or indirect coupling.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements.

What is claimed:
 1. A compressor casing assembly, comprising: a forwardcompressor casing; a removable cover a seal assembly a midcompressorcasing having a cavity adapted to receive the seal assembly, and a covergroove adapted to receive the removable cover; and wherein the removablecover secures the seal assembly.
 2. The compressor casing assembly ofclaim 1, wherein the removable cover is removably fastened to themidcompressor casing.
 3. The compressor casing assembly of claim 1,wherein the cavity is configured to prevent movement of the sealassembly in a radial direction.
 4. The compressor casing assembly ofclaim 1, wherein the seal assembly comprises a T-shaped member having afirst projection and a second projection, and wherein the cavity has anotch adapted to receive the second projection.
 5. The compressor casingassembly of claim 4, a removable cover has a cover notch adapted toreceive first projection.
 6. The compressor casing assembly of claim 1,wherein the removable cover comprises an arcuate member.
 7. Thecompressor casing assembly of claim 1, wherein the forward compressorcasing is disposed in contact with the removable cover.
 8. A turbineengine, comprising: a midcompressor casing having a face surface and aninner surface, the midcompressor casing having a cavity formed on theinner surface and a groove formed on the face surface; a plurality ofarcuate seal segments configured to be inserted into the cavity; aremovable cover disposed in contact with at least one of the pluralityof arcuate seal segments and being removably secured to themidcompressor casing.
 9. The turbine engine of claim 8, wherein each ofthe plurality of arcuate seal segments comprises a sealing surfaceextending a full circumferential length along each of the plurality ofarcuate seal segments.
 10. The turbine engine of claim 9, wherein thesealing surface comprises one of an abradable seal surface, a honeycombseal surface, and a brush seal surface.
 11. The turbine engine of claim8 wherein the removable cover is an arcuate member.
 12. The turbineengine of claim 8 further comprising a forward compressor casingdisposed adjacent to the removable cover.
 13. An assembly, comprising: amidcompressor casing having a face surface and an inner surface, theinner surface having a cavity and the face surface having a covergroove; a plurality of arcuate seal segments configured to be insertedinto the cavity; and a removable cover adapted to be inserted into thecover groove, the removable cover disposed in contact with at least someof the plurality of arcuate seal segments and secured to themidcompressor casing.
 14. The assembly of claim 13, wherein theremovable cover is removably fastened to the midcompressor casing. 15.The assembly of claim 13 wherein the cavity is configured to preventmovement of the plurality of arcuate seal segments in a radialdirection.
 16. The assembly of claim 13 wherein the removable cover isan arcuate member having a peripheral length that is longer than aperipheral length of each of the plurality of arcuate seal segments. 17.The assembly of claim 13 wherein each of the plurality of arcuate sealsegments comprises a sealing surface extending a full circumferentiallength along each of the plurality of arcuate seal segments, the sealingsurface extending a distance above and below a radially inner surface ofthe midcompressor casing when each of the plurality of arcuate sealsegments is coupled the midcompressor casing.
 18. The assembly of claim17 wherein the sealing surface comprises one of an abradable sealsurface, a honeycomb seal surface, and a brush seal surface.
 19. Theassembly of claim 13 wherein each of the plurality of arcuate sealsegments comprises a T-shaped member having a first projection thatengages a notch formed on the midcompressor casing and a cover grooveformed on the removable cover.
 20. The assembly of claim 13 furthercomprising a forward compressor casing disposed in contact withremovable cover.